High schooler and creator of online magazine Rookie, Tavi Gevinson is busy fashioning a DIY media empire that speaks to teens.

In her Beatlemania schoolgirl outfit — gray miniskirt, knee-highs and electric-blue suede shoes — Tavi Gevinson looks like any other fashion-obsessed teen as she wanders the crowded aisles of Los Angeles' American Rag Cie.

"I can't afford, like, anything here on my allowance," the 17-year-old says, scanning the store's horizon for any gems she might have missed.

"My dad, he'll be here in about half an hour to pick me up," she says, heading toward a carousel rack of vintage-image postcards — "the one thing I actually can afford!"

Gevinson is decisive as she plucks out certain moody postcards and quickly discards others. When the wobbly rack catches on the carpet and fails to turn, the petite Gevinson lifts the metal display and firmly plants it a few inches away, where it swirls freely.

"There" she says sweetly. "I'll take these four." After paying, Gevinson tucks the cards away in her floral backpack. "Now, what were we talking about again?"

One can forgive the high school senior for being a bit distracted. After flying in from Chicago, she was up late the night before finishing an essay. But the assignment wasn't for school. It was the editor's letter for Rookie, the online pop-culture magazine she started when she was 15; now she oversees a staff of about 80.There was also a photo shoot this morning, followed by a meeting with her agent and then another whirlwind shopping trip in Hollywood.

After a book signing and reading of "Rookie" magazine at Skylight Books in Los Angeles, Tavi Gevinson, left, pauses to snap a photo with reader Sarah Isenberg. More photos

She will appear at Skylight Books later to sign copies of "Rookie Yearbook Two," an annual print anthology of Rookie's best online writing paired with original content from the likes of Lena Dunham, Mindy Kaling, Judy Blume and singer-songwriter Grimes. The store expects an adoring mob of teenage fans for Gevinson, called "the future of journalism" by no less than Lady Gaga.

Part Tina Brown, part Dorothy Parker, the quick-wittedGevinson has the ear — and Tumblr accounts — of a new generation of young women. Not to mention the eye of the media, the fashion world and, lately, Hollywood filmmakers.

"I'd felt like there wasn't a publication for teenagers that was respected. Or that I, myself, or my friends could really relate to," Gevinson says, settling into a booth at the cafe next door to American Rag,her creamy skin, crimson lipstick and blond bob giving her something of a "Ghost World"-era Scarlett Johansson quality. She slurps her lemonade.

"One thing I'm very proud of is that Rookie has a lot of legitimacy in publishing and music journalism and fashion. As it's grown, the goal has become more to make people feel included, that they're cool enough or smart enough."

Rookie beginnings

The original Style Rookie blog impressed journalist Anaheed Alani so much she offered unsolicited help.

"She emailed me and said: 'I work at the New York Times, and I will quit my job to help you,'" Gevinson says. "It was clear we were on the same wavelength. She's now second in command and my partner in a lot of ways."

Alani, 43, now Rookie's editorial director, has no issues working for a teenage boss.

"Tavi's one of the best bosses I've had," Alani says. "My rule for bosses and therapists is they have to be smarter than I am — and Tavi completely fits that bill."

An instant success when it launched in late 2011, Rookie now boasts jewelry and makeup ads and hosts in-person Rookie events in cities across the country, such as an Urban Outfitters-sponsored road trip last year that included crown-making workshops — Gevinson feels her now-signature floral crowns show "a pride in one's girliness."

In addition to material from the site, the Rookie yearbooks feature exclusive interviews with major pop cultural figures such as Morrissey, Chris Ware and Emma Watson; they're juxtaposed against personal essays by teens on universal issues such as sex, racism, friendship and feminism.

Boiled down, Gevinson's message might be "embrace yourself" — and it seems to be resonating.

"She's really, really popular with L.A. girls," says 16-year-old Xulani Akel, a sophomore at Los Angeles Center for Enriched Studies. "It's so amazing that she's so young and so successful. I'm worried about getting, like, one B, and she has this whole company thing that she's doing and that she really enjoys. That sets the bar really high!"

Fans at a bookstore

Skylight Books is filling up. The teen girls filter in, some wearing brightly colored floral headbands, others in swingy skirts and glittering prom crowns. Most carry a certain dog-eared book tucked under their arms as they swing between intensely focused and bubbling over with excitement.

Like a religious pilgrimage, many come bearing gifts cradled in their arms for Gevinson, who at the moment sits in the store's office loft, overlooking the main floor. Chitchatting with the two Rookie contributors who will be reading with her tonight, Gevinson looks very much her age.

"This'll be fun. Who wants to go first?" she asks them, as if the event were an impromptu school talent show.

Moments later, however, when Gevinson takes the podium before a now settled-in crowd of about 150 rapt girls, she is preternaturally poised as she faces the crowd. She holds her iPhone out in front of her with two hands, as if it were stiff essay paper, and reads off the screen in an adult, measured tone.

Teen blogger sensation and editor-in-chief of "Rookie" magazine, Tavi Gevinson, 17, reads to a throng of teens at Skylight books in Los Angeles. More photos

How is she able to ingest so much pop culture daily, interview her heroes, blog prolifically, write essays for Rookie and oversee her staff — all while attending high school? It's simple time management, she says earlier in the day, at the cafe on La Brea Avenue.

Gevinson spends nearly every sliver of downtime listening to podcasts or music — most recently Lorde, Taylor Swift and Kanye West — while walking to school, for example, or watching old episodes of "Freaks and Geeks" and "My So-Called Life" at night. Study hall, she says, is a perfect time to read other books she finds more relevant in the long run, like "Girl Power" by MarisaMeltzer.

Such efficiency, however, is not without sacrifice.

"There are compromises," Gevinson says. "Like there have been times when my grades have suffered or I can't visit my boyfriend when I'd like to because I have a number of interviews that day. But it's worth it."

Still, Gevinson's parents have made sure to keep her life "full of normal teenage stuff," says her father, Steve. She attends the local public high school and recently got an allowance increase. She doesn't yet earn a salary from Rookie — though that may change soon, he says, as the site becomes more profitable — and speaking engagement fees go into her savings. The total sum of her liquid assets from day to day is her allowance: $25 a week.

"It's a nice little fiction that we're living out because she has this bank account," he says. "But she likes living that way. We like her living that way."

Like many proud "pop culture nerds," Gevinson has a not-so-subtle obsessive streak. She might get up at 3 a.m. to rearrange all her books, she says, and not only journals her life's every happening, from monumental to mundane, but also "curates" her peripheral pop culture experiences to match her moods.

"Sophomore year I had my heart broken by a boy. I loved the feeling of heartbreak with dressing in nightgowns from the '70s, lighting candles and listening to Heart and Carole King," she says. "I documented it all. It's like making a bunch of little movies. It makes me feel like I'm in control and everything has a place in the world."

These days, Gevinson's mood is often a mix of excitement and trepidation. She's awaiting graduation in May and has applied to New York University, Barnard, Brown and Wesleyan — though she'd like to take a year off first to live in New York and focus on Rookie as well as other creative ventures, such as acting.

"Tavi walked in [to auditions], this little lovely thing, an angel with red lips and pink cheeks," Holofcener says. "She was maybe more nervous than someone who's been in a million films, but that nervousness was so natural and vulnerable and sweet. She left the room and I said, 'I want her.'"

How does all this high-profile success translate in the halls, on an everyday basis, at school in suburban Illinois?

Stirring the straw in her lemonade, Gevinson plays down her success, insisting that most kids at her school are either unaware of her growing fame or they don't particularly care.

Suddenly, three eager heads poke out of a nearby booth, their hands waving furiously at Gevinson. "Hi, Tavi!" they squeal in unison. "We love you."

Gevinson shrugs and breaks into a little-girl smile herself, giggling at the absurdity. "Oh, I guess they recognize me," she says.

On her way out of the cafe, Gevinson pauses at the door.

"I just hate 'voice of a generation' stuff," she says, balking at the suggestion. "You put someone on a pedestal and of course they can't represent all of feminism or all people their age or whatever."

And with that, Gevinson scurries out to the parking lot to meet her dad, her books and notes for the evening's reading bundled in her arms.